A monochromator is a device that splits a broad band of light into individual bands of various wavelengths and individually displays a band or bands of a desired wavelength or wavelengths. A diffraction or transmission grating is customarily used to split the original light band. A grating is similar in function to a modern-day prism. In the past, prisms were used in monochromators to perform the function now performed by gratings.
In present-day monochromators, the grating splits light when the grating is mechanically rotated by a motor, or by hand, past a slit. Thus, the split wavelengths are scanned in the order in which they are found in a light spectrum. Grating type monochromators were developed to solve problems associated with the nonlinear or second order dispersion of light commonly exhibited by prisms.
This invention enables one to vary bandwidths of light. This, in turn, will correct for the aforementioned deficiency in prisms, and thus permits prisms to be used again as dispersive elements in the novel random access monochromators described herein.